E39 - Infamous water reservoir problem...

[Danion]

Hello all, (Sorry for the long read but I really want to fix my beautiful car!)

I recently bought a E39 with 180k km's. After 2 test drives I deemed it perfect and along with cash and a kidney, I purchased my very first car. My father has always driven BMW's, so I have always wanted one as well. 
The car came with barely any faults to what I could tell. There were some obvious small (!) scratches, and the back window pump doesn't really work. That's it. Those were the faults! It came with every possible book, paper, receipt it had ever endured or went through so it felt as a good deal. Every button, every electronical gadget works! 

However... Thats where the good news stops. After the massive, massive rain fall in the last couple of weeks, I noticed that my breaks were not working properly all of a sudden. They sounded drowned, whenever I pressed the pedal, as if they were full of water? It was weird, and I had no idea what the hell was causing it. 
It stilled braked properly, but it just sounded weird. I asked my father and he had no clue. (I work 65 hours a week, so as a moron, I just left it at that..) 

During the days, I noticed some white smoke coming from the exhaust, very rarely, but just a sudden puff, but just as that, it was gone again. 
Long story short, que today. Doomsday. 
I drive towards work and it is absolutely pouring out. I went through immense puddles since it wasn't draining well, and the rain was battering down. As I arrive to work, I can't go straight down the street, due to a lorry offloading some items. I reverse and turn around. All of a sudden, I hear this massive racket coming from the engine. It was best described as a 'tok tok tok tok tok' sound, perfectly in rhythm with the engine. Having no knowledge about cars, I knew this was bad. Thankfully the parking lot was around the corner so I drive there in a snail pace and quickly shut it down, fearing the worst. 
I call a mechanic and he comes by, and while inspecting the car, he tells me its dead. Its totaled. Best I could get, was 200 bucks as old iron. He revved it once during the inspecting and while doing so, the 'tok tok tok' noise became louder and then it was unable to keep its revs up and it died, showing the 'check engine light' 

He leaves, telling me a whole bunch of things are wrong with the car, and its just completely broken down, reducing it to nothing but a cheap piece of iron. 
I have zero experience with cars. None, zhilts, nadda, nothing. I have two left hands, and here I stand with a broke car. 
I call my father, quite desperate but he lives in France, so not really close by.... He tells me basically the same thing as the mechanic and that I could either have it written off, dragged on a trailer home (which would cost extra money) or by a revised engine. 

An hour later however, he tells me something he had found online what could actually be the source of the problem! The water! Mind you, again, I have no knowledge of cars but apparently the water inside that reservoir has somehow gone into the engine and that has caused it to stall and most likely did some horrific damage inside. However... if I were to drain the water, remove the air filters, take of the spark plug (holders?), the spark plugs themselves and then clean the piston chambers (I think thats' correct) I might save it from total devastation. 

Right. 
No clue. 

It took me 7 hours, with no tools at all that I had to buy all across town, but I managed to remove the air filter and then drained the reservoir. First I removed the grime and dirt by hand, and then with towels until it was completely dry. 
Then I removed the head cover and the spark plug holders, the spark plugs and then cleaned out of the... pipes. The objective was to see if there was water inside. 5 out 6 pistons were clean, although the 3 spark plugs were quite covered in oil. 1 piston chamber had actually water in it and it took me an hour to dry it out carefully. 

After I refitted everything back, it was the moment of truth and start the car. It actually started but it was far from stationaire. It wasn't basically. I let it run in idle for a good while to remove the extra water, and slowly but surely the engine started to run more smoothly. There was tons of white smoke coming out of it, but the longer it ran, the less it became. 
If you revved it, it sometimes died and it had difficulty starting after that but has now dissapeared. 

I have now driven it home after they said it was totaled and it remains perfectly stationaire. I can rev it and it just smoothly drops back to idle. There is no white smoke either. 

HOWEVER!? There is a weird soft rattling sound if you rev it. If you drive it and accelerate the rattling becomes louder, until you drop between 1.5-2k revs. If you get your foot of the gas the noise is completely gone, but after you give it gas, it comes back. I have driven 50km after I got home and stopped the car and restarted it quite a few times to see how it behaved and for all intents and purposes, its like nothing happend. EXCEPT, that rattling sound. I already dived into the internet and found that it could be the DISA valve? 
Or is there still some catastrophic damage within that simply can't be fixed? 
And yes, obviously I will bring it in for service to see what they can find. 

Anyway, that's my story and question. I have learned more about cars today then I have done in my life time, and quite honesty, loved it!
Now, if I can get that rattling noise away, that would be a proper fix! 

Thanks in advanced if you have any idea!

Kind regards

As you can see, its filled up. 

 

[Greydog]

Morning 

It seems you have been very lucky 

You need to check all drain holes they have small rubber flaps that can get blocked with leaves and stuff over time to make sure your engine bay doesn't get flooded again.  

Change the oil and check carefully for signs of water in the oil and filter also worth changing the fuel filter as well

Good Luck

Dave

[Danion]

Morning!

Thank you for the advice! I will give that a go, but since I have nothing of the tools, I will have to go buy them first. 
Fingers crossed!